In processing (etching) process of semiconductor as a typical example of fine patterning, the semiconductor surface is irradiated with reactive gas in plasma state, and the semiconductor is processed into desired shape.
Explaining briefly by referring to FIG. 9, a vacuum chamber 1 is coupled to a vacuum pump 2 for creating vacuum. A processing object like silicon wafer 3 is placed in the vacuum chamber 1, and desired gas is introduced, and plasma 4 is generated to cause interaction with the surface of the processing object, and the processing object is processed. In FIG. 9, the processing object is etched.
Meanwhile, as disclosed in Japanese Patent Unexamined Publication No. H9-27654, the conventional etching was often processed by immersing the solid processing object in liquid. However, etching in the liquid is sufficiently fast in etching processing speed, but is not suited to fine patterning because etching tends to be isotropic.
The reason of using plasma in etching is to make etching anisotropic in order to meet the demand for higher precision in fine patterning.
However, when plasma is used in etching, the processing speed is sacrificed. As a result, in the semiconductor industrial field, typically, it took about 10 minutes to process one wafer.